1. Field of the Invention
The present invention relates to a pressure sensor device and a pressure sensor device manufacturing method.
2. Description of the Background Art
Generally, a semiconductor pressure sensor chip that utilizes a piezoresistance effect is used as a sensor element in a pressure sensor device that measures pressure by being attached to a transmission oil seal block, hydraulic actuator block, or the like, of an internal combustion engine or the like. The semiconductor pressure sensor is of a configuration wherein a multiple of semiconductor strain gauges are connected in a bridge on a diaphragm made of a material having a piezoresistance effect, such as monocrystalline silicon. When the diaphragm is distorted by pressure change, the gauge resistance of the semiconductor strain gauge changes in accordance with the amount of distortion, and the amount of the change is extracted from the bridge circuit as a voltage signal.
At present, a device wherein a pressure sensor chip incorporating a diaphragm, a piezoresistance element, an amplifier circuit, and various kinds of regulator circuit is joined to a base member so that the diaphragm is aligned with a through hole of the base member is publicly known as a pressure sensor device (for example, refer to Japanese Patent No. 4,839,648, Japanese Patent No. 5,278,448, and JP-A-10-78365). When using this kind of pressure sensor device in a high pressure zone, it is necessary that a pressure introduction unit joined to the base member is configured of a metal material. Also, an adhesive (for example, a silicon (Si) series adhesive) is used in the joining of the pressure introduction unit and a resin case in which the pressure sensor chip is housed, so that the pressure sensor chip does not detect thermal contraction of the resin case as a pressure change.